我正在使用MySQL Tutorial's sample database。
我需要找到每个venta_por_empleado和venta_por_empleado的销售业绩最差（最低semestre）和最佳销售（最高city）的销售人员。使用temporary表，我得到以下结果集（tbl_ventas_ciudad_semestre，一个临时表）：
| salesRepEmployeeNumber | Nombre_Empleado | city | venta_por_empleado | officeCode | orden_year | semestre | periodo |
|------------------------|------------------|---------------|--------------------|------------|------------|----------|---------|
| 1504 | Barry Jones | London | 6719 | 7 | 2019 | 1 | 2019-1 |
| 1286 | Foon Yue Tseng | NYC | 5016 | 3 | 2019 | 1 | 2019-1 |
| 1323 | George Vanauf | NYC | 6372 | 3 | 2019 | 1 | 2019-1 |
| 1702 | Martin Gerard | Paris | 4180 | 4 | 2019 | 1 | 2019-1 |
| 1401 | Pamela Castillo | Paris | 8464 | 4 | 2019 | 1 | 2019-1 |
| 1370 | Gerard Hernandez | Paris | 12021 | 4 | 2019 | 1 | 2019-1 |
| 1166 | Leslie Thompson | San Francisco | 3587 | 1 | 2019 | 1 | 2019-1 |
| 1165 | Leslie Jennings | San Francisco | 11208 | 1 | 2019 | 1 | 2019-1 |
| 1611 | Andy Fixter | Sydney | 5550 | 6 | 2019 | 1 | 2019-1 |
| 1621 | Mami Nishi | Tokyo | 4923 | 5 | 2019 | 1 | 2019-1 |
| 1501 | Larry Bott | London | 7776 | 7 | 2019 | 2 | 2019-2 |
| 1337 | Loui Bondur | Paris | 6186 | 4 | 2019 | 2 | 2019-2 |
| 1188 | Julie Firrelli | Boston | 4227 | 2 | 2020 | 1 | 2020-1 |
| 1612 | Peter Marsh | Sydney | 6036 | 6 | 2020 | 1 | 2020-1 |
| 1216 | Steve Patterson | Boston | 4876 | 2 | 2020 | 2 | 2020-2 |
要找到销售最差的销售人员，我将MIN(venta_por_empleado)应用于表中：
SELECT
Nombre_Empleado,
city,
MIN(venta_por_empleado) as venta_por_empleado,
orden_year,
semestre,
periodo
FROM tbl_ventas_ciudad_semestre
GROUP BY
city, periodo
ORDER BY
periodo ASC, venta_por_empleado DESC;
结果：
| Nombre_Empleado | city | venta_por_empleado | orden_year | semestre | periodo |
|-----------------|---------------|--------------------|------------|----------|---------|
| Barry Jones | London | 6719 | 2019 | 1 | 2019-1 |
| Foon Yue Tseng | NYC | 5016 | 2019 | 1 | 2019-1 |
| Martin Gerard | Paris | 4180 | 2019 | 1 | 2019-1 |
| Leslie Thompson | San Francisco | 3587 | 2019 | 1 | 2019-1 |
| Andy Fixter | Sydney | 5550 | 2019 | 1 | 2019-1 |
| Mami Nishi | Tokyo | 4923 | 2019 | 1 | 2019-1 |
| Larry Bott | London | 7776 | 2019 | 2 | 2019-2 |
| Loui Bondur | Paris | 6186 | 2019 | 2 | 2019-2 |
| Julie Firrelli | Boston | 4227 | 2020 | 1 | 2020-1 |
| Peter Marsh | Sydney | 6036 | 2020 | 1 | 2020-1 |
| Steve Patterson | Boston | 4876 | 2020 | 2 | 2020-2 |
要找到销售最好的销售人员，我将MAX(venta_por_empleado)应用于表中：
SELECT
Nombre_Empleado,
city,
MAX(venta_por_empleado) as venta_por_empleado,
orden_year,
semestre,
periodo
FROM tbl_ventas_ciudad_semestre
GROUP BY
city, periodo
ORDER BY
periodo ASC, venta_por_empleado DESC;
| Nombre_Empleado | city | venta_por_empleado | orden_year | semestre | periodo |
|-----------------|---------------|--------------------|------------|----------|---------|
| Barry Jones | London | 6719 | 2019 | 1 | 2019-1 |
| Foon Yue Tseng | NYC | 6372 | 2019 | 1 | 2019-1 |
| Martin Gerard | Paris | 12021 | 2019 | 1 | 2019-1 |
| Leslie Thompson | San Francisco | 11208 | 2019 | 1 | 2019-1 |
| Andy Fixter | Sydney | 5550 | 2019 | 1 | 2019-1 |
| Mami Nishi | Tokyo | 4923 | 2019 | 1 | 2019-1 |
| Larry Bott | London | 7776 | 2019 | 2 | 2019-2 |
| Loui Bondur | Paris | 6186 | 2019 | 2 | 2019-2 |
| Julie Firrelli | Boston | 4227 | 2020 | 1 | 2020-1 |
| Peter Marsh | Sydney | 6036 | 2020 | 1 | 2020-1 |
| Steve Patterson | Boston | 4876 | 2020 | 2 | 2020-2 |
使用MIN（）和MAX（）返回销售编号的正确值，但是与这些销售编号相关联的销售人员的姓名不匹配。
如何获得正确的销售编号的正确名称？
您可以通过联合查询来满足此要求。下面的逻辑采用两个子查询的并集，这两个子查询分别查找每个学期/期间具有最低和最高薪水的记录。我们还包括一个称为position的计算列，该列跟踪每组中出现的两个记录之一是最小记录还是最大记录。对于给定学期/期间只有一个记录的情况，该记录将出现两次。
SELECT
Nombre_Empleado,
city,
venta_por_empleado,
orden_year,
semestre,
periodo
FROM
(
SELECT
t1.Nombre_Empleado,
t1.city,
t1.venta_por_empleado,
t1.orden_year,
t1.semestre,
t1.periodo,
1 AS position
FROM tbl_ventas_ciudad_semestre t1
INNER JOIN
(
SELECT
semestre,
city,
MIN(venta_por_empleado) AS min_venta_por_empleado
FROM tbl_ventas_ciudad_semestre
GROUP BY
semestre,
city
) t2
ON t2.semestre = t1.semestre AND
t2.city = t1.city AND
t2.min_venta_por_empleado = t1.venta_por_empleado
UNION ALL
SELECT
t1.Nombre_Empleado,
t1.city,
t1.venta_por_empleado,
t1.orden_year,
t1.semestre,
t1.periodo,
2
FROM tbl_ventas_ciudad_semestre t1
INNER JOIN
(
SELECT
semestre,
city,
MAX(venta_por_empleado) AS max_venta_por_empleado
FROM tbl_ventas_ciudad_semestre
GROUP BY
semestre,
city
) t2
ON t2.semestre = t1.semestre AND
t2.city = t1.city AND
t2.max_venta_por_empleado = t1.venta_por_empleado
) t
ORDER BY
semestre,
periodo,
position;